For the "DITA Map WebHelp Responsive" transformation scenario in Oxygen Author 21, the location of the publication TOC in each topic is changed from the right side to the left side. I guess I can change it back to the right side by editing the wt_topic.html file, but I'm not sure what classes to use.

Can anyone give me a hand?

BTW, it would be great if we can control that with a parameter, like "webhelp.show.publication.toc".

Indeed, in version 21 of oXygen XML the publication TOC is shown on the right side. This was moved as on the left side there is a topic table of contents, You can check the current WebHelp Responsive layout here: Layout of the Responsive Page Type

You may try to move the position of the publication TOC from left to the right side using a customization, but note that this may overlap with the topic TOC.